Re: [PATCH v2] rcu: ensure kernel/rcu/rcu.h can be sourced/used stand-alone

[Paul Gortmaker <paul.gortmaker@windriver.com>]

[Re: [PATCH v2] rcu: ensure kernel/rcu/rcu.h can be sourced/used stand-alone] On 19/02/2014 (Wed 17:53) Paul E. McKenney wrote:

> On Wed, Feb 19, 2014 at 02:33:27PM -0500, Paul Gortmaker wrote:
> > The kbuild test bot uncovered an implicit dependence on the
> > trace header being present before rcu.h in ia64 allmodconfig
> > that looks like this:
> > 
> > In file included from kernel/ksysfs.c:22:0:
> > kernel/rcu/rcu.h: In function '__rcu_reclaim':
> > kernel/rcu/rcu.h:107:3: error: implicit declaration of function 'trace_rcu_invoke_kfree_callback' [-Werror=implicit-function-declaration]
> > kernel/rcu/rcu.h:112:3: error: implicit declaration of function 'trace_rcu_invoke_callback' [-Werror=implicit-function-declaration]
> > cc1: some warnings being treated as errors
> > 
> > Looking at other rcu.h users, we can find that they all
> > were sourcing the trace header in advance of rcu.h itself,
> > as seen in the context of this diff.  There were also some
> > inconsistencies as to whether it was or wasn't sourced based
> > on the parent tracing Kconfig.
> > 
> > Rather than "fix" it at each use site, and have inconsistent
> > use based on whether "#ifdef CONFIG_RCU_TRACE" was used or not,
> > lets just source the trace header just once, in the actual consumer
> > of it, which is rcu.h itself.  We include it unconditionally, as
> > build testing shows us that is a hard requirement for some files.
> > 
> > Reported-by: kbuild test robot <fengguang.wu@intel.com>
> > Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
> 
> Queued for 3.16, thank you, Paul!

Thanks!

I'm assuming you meant 3.15 -- unless of course you are allowing
for an insurance policy for me possibly breaking the build.  ;)

P.
--

> 
> 							Thanx, Paul
> 
> > ---
> > 
> > [v2: move the #include <trace/events/rcu.h> outside of the scope
> >  of #ifdef CONFIG_RCU_TRACE so it is unconditionally included.]
> > 
> >  kernel/rcu/rcu.h    | 1 +
> >  kernel/rcu/srcu.c   | 2 --
> >  kernel/rcu/tiny.c   | 4 ----
> >  kernel/rcu/tree.c   | 2 --
> >  kernel/rcu/update.c | 1 -
> >  5 files changed, 1 insertion(+), 9 deletions(-)
> > 
> > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > index 1bd787fddcb2..3d2a037332b2 100644
> > --- a/kernel/rcu/rcu.h
> > +++ b/kernel/rcu/rcu.h
> > @@ -23,6 +23,7 @@
> >  #ifndef __LINUX_RCU_H
> >  #define __LINUX_RCU_H
> > 
> > +#include <trace/events/rcu.h>
> >  #ifdef CONFIG_RCU_TRACE
> >  #define RCU_TRACE(stmt) stmt
> >  #else /* #ifdef CONFIG_RCU_TRACE */
> > diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
> > index 5db7e9272d37..8e66b05bfd82 100644
> > --- a/kernel/rcu/srcu.c
> > +++ b/kernel/rcu/srcu.c
> > @@ -36,8 +36,6 @@
> >  #include <linux/delay.h>
> >  #include <linux/srcu.h>
> > 
> > -#include <trace/events/rcu.h>
> > -
> >  #include "rcu.h"
> > 
> >  /*
> > diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
> > index 53b95bbf4abb..d9efcc13008c 100644
> > --- a/kernel/rcu/tiny.c
> > +++ b/kernel/rcu/tiny.c
> > @@ -37,10 +37,6 @@
> >  #include <linux/prefetch.h>
> >  #include <linux/ftrace_event.h>
> > 
> > -#ifdef CONFIG_RCU_TRACE
> > -#include <trace/events/rcu.h>
> > -#endif /* #else #ifdef CONFIG_RCU_TRACE */
> > -
> >  #include "rcu.h"
> > 
> >  /* Forward declarations for tiny_plugin.h. */
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index c7a00dbe768b..351faba48b91 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -58,8 +58,6 @@
> >  #include <linux/suspend.h>
> > 
> >  #include "tree.h"
> > -#include <trace/events/rcu.h>
> > -
> >  #include "rcu.h"
> > 
> >  MODULE_ALIAS("rcutree");
> > diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
> > index fd0d5b5b8e7c..4c0a9b0af469 100644
> > --- a/kernel/rcu/update.c
> > +++ b/kernel/rcu/update.c
> > @@ -49,7 +49,6 @@
> >  #include <linux/module.h>
> > 
> >  #define CREATE_TRACE_POINTS
> > -#include <trace/events/rcu.h>
> > 
> >  #include "rcu.h"
> > 
> > -- 
> > 1.8.5.2
> > 
>